INFLUENCE OF SURFACE-ENERGY ON THE GROWTH OF 6H-SIC AND 4H-SIC POLYTYPES BY SUBLIMATION

Large SiC crystals can be grown by a sublimation process. For electronic application the control of the growth of a definite polytype is important. We have shown that sublimation growth on the Si[0001] side, under given conditions, always crystallizes the 6H polytype regardless of the polytype of the seed. Under the same conditions on the C[0001] side, the 4H polytype crystallizes. The reason for this behaviour is thought to be the different surface energy of the silicon and carbon sides. The difference of 4H and 6H formation energy is compared with the difference of the reaction energy of oxidation on silicon and carbon sides.